1. Field of the Invention
The present invention relates to castors for associating with any object of the furniture type in order to make it easier to move, the castor essentially comprising two wheels, a casing for supporting and possibly protecting the wheels, and a pivot that provides the connection between the casing and a piece of furniture.
2. Description of the Related Art
In particular but non-exclusive manner, numerous such castors find an especially advantageous application in making it easier to move hospital equipment and furniture, e.g. trolleys, wheelchairs, carts, walking frames, etc., and also suitcases and the like.
The structure of such a castor must therefore be designed so that it makes it easy to move such a piece of furniture in any direction. In particular, for this purpose, it generally has two parallel-mounted wheels, means for enabling the two wheels to rotate about a horizontal axis relative to the casing in order to run on the ground for the purpose of enabling the piece of furniture to move in translation in a straight line, and means for enabling the casing to pivot relative to the piece of furniture about an axis that is substantially vertical in order to enable the castor to occupy any direction relative to the piece of furniture and thus enable the piece of furniture to be steered easily around curves.
Nevertheless, for example at the end of its movement when the piece of furniture has reached its final position, it is generally necessary to prevent the furniture from moving, if only accidentally. It is therefore preferable for the castors that are mounted on the piece of furniture then to become locked automatically, at least in terms of rotation, so as to prevent them from running on the ground, with this applying more particularly for trolleys, walking frames, suitcases, etc., and for the castors to be unlocked as a result of the user performing a voluntary action.
By way of example, such a castor is described in EP 2 556 768, FR 2 895 702 and DE 103 18 308, and more particularly in WO2012/035213.
In addition to the means defined below, the castor includes locking-and-unlocking means for locking and unlocking the two wheels relative to the casing. These locking-and-unlocking means comprise at least one set of female notches made in at least one of the two faces of the wheels that face towards the casing, a lever mounted to co-operate with the casing, at least one male lug complementary to the female notches, means for securing the male lug to the lever, the lever being mounted to pivot on the casing in such a manner as to be suitable for occupying at least two positions, a first position in which the male lug does not co-operate with any of the female notches, and a second position in which the male lug is positioned in one of the female notches, a pull connection, and means for connecting a first end of the pull connection to the lever in order to cause the lever to pass from its first position to its second position.